Hi I had the same problems using ver 4.0 and followed your advice to try the Development Version. It worked for activation but the actual contact form failed to work.
Even with the new upgrade to 4.0.1 I’m still experiencing problems getting the form to work correctly. The email submissions seem to fail and not get sent.
I too am hoping you can figure this out. Thanks!!!
PS I’m running WP version 4.0
